As is well known, trees and plants through the process of photosynthesis naturally convert CO2 into oxygen. When nature cannot do its job, chemistry takes over. In manned, enclosed atmospheres such as rescue chambers, dive devices or submarines, two chemical technologies have historically been employed to scrub the CO2 from the environment: lithium hydroxide and soda lime. Below are the pros and cons of both materials.
Lithium Hydroxide Soda Lime w/ ScrubberCurtainsCO2 Absorption:150 liters CO2 per kg402 liters CO2 per kgPackaging:20 kg (44 lb) sealed 8 curtains per box; 5.72 kegslbs of LiOH per box.96 Hr 1 keg per man2.75 boxes per manRequirements:Per MSHA: (.244 lbs/man-hr) * 96 hr/5.72 lbs/box = 4.1 boxesApprox Cost/unit:$135/keg$487/boxCost/man for $135/man$1339/man96 hrs:$1997/man per MSHAShelf Life:5 years5 years; must be discardedHeat Generated:32 Btu's per man per 130 Btu's per man per hourhour; curtains actually hot to the touchDeployment:Simple; new keg addedComplicated; curtains when color changesmust be hung at a set schedule and spacingEffectiveness:good air circulation fromonly works in small, Air driven fanconfined areas; not effective in large areasPower None; air/oxygen None; passive system Requirements:driven fanrelies on localized natural convective currents